1. Field of the Invention
Apparatuses consistent with the present invention relate to an analog correlator for very high speed data communication, and more particularly, to an analog correlator for very high speed data communication using a transmission line and a lumped element.
2. Description of the Related Art
In general, the mobile communication field has recently drawn attention, and the digital mobile communication has especially been rapidly developed by using base technology such as CDMA. A correlator is essentially used for synchronization demodulation in a communication apparatus using the CDMA. The correlator mostly uses digital methods.
The current digital communication has improved for high speed transmission. The conventional digital correlator cannot be embodied at a high transmission speed. That is, the conventional correlator using the digital technology cannot technically accept the digital communication increasing its speed. Since a chip period that is a clock composing the CDMA has a much higher speed than the transmitted information by a few orders of magnitude, it is difficult to embody a demodulator as the digital correlator.
FIG. 2 is a view illustrating a conventional impulse correlator using an RF mixer. The impulse correlator includes an RF mixer 200, a template generator 140, an integrator 150 and an A/D converter 160. The operational principle of the conventional impulse correlator using the RF mixer will now be explained with reference to FIG. 2. When receiving an input signal 210, the template generator 140 generates a template signal 220 in the same type as the input signal 210, matches synchronization of the input signal 210 and the template signal 220, multiplies the signals 210 and 220 by the RF mixer 200, integrates the signals 210 and 220 by the integrator 150, and samples the signals 210 and 220 through the A/D converter 160.
However, in the above method, it is difficult to embody a broadband mixer and the template generator 140 for matching synchronization with the input signal 210 according to variations of the channel environment. Also, power consumption increases.
FIG. 3 is a view illustrating a conventional correlator using a digital delay circuit. The conventional correlator using the digital delay circuit receives an A/D converted signal 300, and processes the signal 300 in a digital domain. Therefore, the conventional correlator can be applied to various types of signals. However, although a high speed AID converter 160 is necessary for short pulses, it is impossible to process signals in the very high speed data communication environment by using the A/D converter 160.